Adaptive protection of transmission lines during wide area disturbances

The behavior of transmission line protection relays during wide area disturbances may have a significant impact on the development of the disturbance and its final collapse. The paper analyzes the changing system conditions that occur during a disturbance and how they impact protection systems of different types. Available tools and how they can be used to adapt the protection to the changing environment and ensure faster fault clearing time are described. Requirements and methods for testing of adaptive protection systems are discussed at the end of the paper.